Tribunal President Erasmo Pinilla says that with 44 percent of the votes counted Martinelli is the "indisputable winner" of Sunday's voting.

Martinelli, of the opposition Alliance for Change, topped former Housing Minister Balbina Herrera of Panama's governing coalition, which is led by the Democratic Revolutionary Party. Pinilla said he telephoned Martinelli to inform him of his victory.

The winner, whose term ends in 2014, will have to guide Panama through the world economic crisis and the $5.25 billion expansion of the canal to increase its capacity and accommodate larger ships.